Device for supplying starting fuel



July 2y 1945; a. N. HoFFsTRoM 42,64

DEVICE .FOR SUPPLYING STAR'IIIIG' FUEL Filed Jan. 1l, 3.943

r2 110e# iLo'r: 50 /V. Half-Fs THU/w Patented July 2, 1946 UNITED STATESPATENT DEVICE FOR SUPPLYING STARTING FUEL Bo N. Hoffstrm, Malmo, Sweden,assigner to A.B. Aerotransport, Stockholm, Sweden, a corporation ofSweden Application January 11, 1943, Serial No. 472,084 In SwedenDecember 1,1941

11 Claims. 1

The present invention refers to devices for supplying starting fuel tointernal-combustion engines, particularly aircraft engines, by means ofan injection nozzle opening into the inlet channel of the engine.

The principal object of the invention is to provide an improved deviceof the type indicated which can be relied upon to facilitate thestarting of internal-combustion engines even in cool weather when theneed fo-r supplying a starting fuel is greatest.

Another object of the invention is to provide a device of the typeindicated by which a special fuel, which has a sufciently high vaporpressure even at low temperatures to form a combustible mixture with airand which is therefore suitable for the starting of internal-combustionengines,

' can be supplied to the latter.

A further object of the invention is to provide a device of the type inquestion which is capable of proportioning the injected quantity of fuelso that the engine receives neither too much nor too little fuel.

A still further object of the invention is to provide a device of thetype in question which can be electromagnetically controlled from thecockpit of an aeroplane, by means of a single and light mechanism.

n rther objects and advantages of the invention will appear from thefollowing description thereof.

The invention is illustrated in the accompanying drawing in a preferredembodiment. In the drawing Figure l is a diagrammatic View showing howthe fuel supply device of the invention is used in an internalcombustion engine.

Fig. 2 is a vertical section through a unit composed of a remotecontro-lled valve and an injection nozzle, said u nit being inserted inthe wall of the inlet channel of an engine.

Fig. 3 is a detailed cross-sectional View of the core and valve needleon the line 3-3 of Fig. 2.

Fig. 4 is a fragmentary axial sectional view of the nozzle head.

The device illustrated in Fig. 1 consists of a starting fuel tank withassociated mounting and coupling means and a valve and nozzle unit 29which is mounted on the inlet-pipe of the engine 2 4and is connectedWith the fuel tank through a pipe or hose conduit 43. The fuel tank maybe mounted at any suitable place on the aeroplane or other vehicle withwhich the engine is associated. In multi-engine aircraft a starting fueltank may be provided for every engine, whereby long pipings are avoided.The fuel employed can be chosen at will to suit various conditions, b'utit should be such that it has a relatively high vapor pressure also atlow temperatures. If desired, a fuel having a vapor (Cl. 12S- 180)pressure which at ordinary temperatures substantially exceeds theatmospheric pressure may be used. The tank is filled for example to twothirds with the fuel, while the remaining volume is filled with asuitable inert gas under pressure, e. g. carbon dioxide or nitrogen gas.

The fuel tank consists of a closed cylindrical vessel l, which is madeto endure a considerable overpressure. The tank: standing vertically iscarried by a bracket 3, to which it is removably fastened.

The valve and nozzle unit, which is illustrated in Figure 2, consists ofa fitting 26 which is inserted in a hole in the wall of the inletchannel 27 of the'engine, preferably closely infront of the fan (notshown in the drawing) which compresses and propels the fuel-air mixtureto the cylinders. On the inner side of the fitting an injection nozzleor atomiser 2B is screwed in. This nozzle may be of a well-knownconstruction and is shown as having a conical head 28a with grooves 28htherein leading to 'a jet orifice 28e. On the outer side of the fitting26 a remote-controlled valve 29 is mounted. This valve which is of theelectromagnetic type, consists .of a cylindrical housing 30 ofnon-magnetic material which is screwed into a socket on the fitting 26against a sealing packing 3l and carries the other parts of the valve.On the outer side of the housing 30 a solenoid 32 is provided, andWithin the housing a tubular iron core 33 is slidable. In the boring ofthe iron core a valve needle 34 of a considerable length in relation toits thickness is guided for axial movement by at least one circular rowof pins 35 fastened in the iron core and projecting radially inwards insuch a manner as to define a central guide passage for the needle 34without blocking the boring. At its inner end the valve needle is formedwith a valve cone which cooperates with a valve channel 36 which isformed inthe material of the fitting 25 and leads to the nozzle 23. Thevalve cone is made very thin, to reduce the force which the fuelpressure exerts when the valve is closed. The opposite end of the valveneedle is supported by a collar or piston-like disc 3l which is slidablein the housing 30 and is provided with holes for the passage of thef-uel. The disc 31 has a certain radial play in the housing which isslightly greater than the size of the largest solid particles which maybe present in the fuel even if it is strained, in order that the discmay not be jammed on account of these particles. Between this disc 3land the adjacent end of the iron core 33 there is provided a helicalspring 38 which when the valve is closed is only slightly tensioned andthrough which the movement of the iron core outwards at the energizationof the solenoid 32 is transmitted to the valve needle 34 for opening thevalve. Owing to the spring 38 keeping the disc 31 and the iron corespaced from each other,'the iron core has time, before the valve needlecan begin to move, to accumulate a certain amount of kinetic energywhich, upon im-L pact of the iron core against the disc, is made use offor moving the valve needle against the fuel pressure. It is thereforepossible to use a smaller solenoid 32 than would be required in case themagnetic force would have to overcome the fuel pressure directly. Bymeans of the spring 38 the valve needle is dynamically isolated from theiron core 33, so that it is not prevented owing to the inertia of theiron core from following the vibration of the stationary parts duringthe operation of the engine. The valve needle itself has so small a massthat the force exerted by the fuel pressure well suffices for holdingthe valve needle pressed against its vibrating seat irrespective of itsown inertia. On account of the play of the disc 31 in the housing 30vibrations between the latter and the disc can take place in the radialdirection, but owing to the great length of the needle the amplitude ofvibration corresponds to such a small angle of deviation of the needleat its Vseat that the sealing of the valve cone does not suffer. Asecond helical spring 39, which'is placed between the disc 31 and a plug40 screwed into the outer end of the housing 30 and acts on the valveneedle in the direction towards its seat, serves to shut the valve whenthe energization of the solenoid has ceased. The plug 4U has an axialboring 4l in which a fuel filterv 42 is arranged which determines themaximum size of the solid particles which can accompany the fuel throughthe valve and thereby,-asfexplained above, the radial play of the disc31. The outer end of the plug is formed as a nipple for the connectionofthe pipe conduit from'the fuel tank I. l The solenoid 32 is connectedin a circuit 32a which can be closed and broken by a switch 32hforexamplefrom the cockpit in an aeroplane. Preferably, the solenoid isconnected in parallel with thestarting coil. If desired, it may insteadbe 'connected in parallel with the starting motor, the supply ofstarting fuel taking place automatically when the starter is pressed. Y

`When the fuel tank i is mounted in place, the fuel is undercpressureright up to the valve 29, and when this valve is opened by the meansdescribed above, the fuel will therefore immediatelyl'flow into thenozzle 28. The latter is dimensioned to give a suitable proportion ofmixture of the starting fuel and the air drawn-in. The reduction ofthe4pressure in the tank which takes place as the fuel is consumed does notinfluence the proportion of mixture to such a degree that the explosionlimit is exceeded. When 4the fuel tank is empty it can be replaced by anew one with a turn of the? hand,

It has beenassumed above'that the fuel tank is vto be mounted on theaircraft the engine or engines of which it is to provide with additionalfuel, but this is not necessary. The vtank may alsobe mounted on aservo-carriage on the aireld and a hose conduit from the tank betemporarily connected with the nozzle on the engine by means of acoupling device such as that described. y o

Although the invention has been described above in connection withaircraft engines, itvmust not be considered limited to these. It mayequally Awell be employed for fuel supply to other intermal-combustionengines than"'aircraftengines,4 among others'to engines driven `bygenerator gasl 4 Y to give assistance at the starting, hill-,climbingetc.

What I claim and desire to secure by Letters Patent is:

l. A device of the type described, comprising a fuel tank, couplingmeans for said tank, nozzle means for introducing fuel into an engine, aconduit connecting said nozzle means with said coupling means, valvemeans including an axially movable valve needle and inserted in saidconduit, a solenoid, an iron core movable within said solenoid, Vanintermediate member connecting said iron core with said valve needle fordelayed transmission of movement from said iron core to said valveneedle in the valve opening direction against the action of fuelpressure, and an electric circuit for energizing said solenoid.

2. A device of the type described, comprising a fuel tank, couplingmeans for said tank, nozzle means for introducing fuel into an engine, aconduit connecting said nozzle means with said coupling means, valvemeans including an axially movable valve needle and inserted in saidconduit, a solenoid, an iron core movable within said solenoid, anelastic intermediate member connecting said iron core with said valveneedle for building up a force on the latter in the valve openingdirection to overcome the force of fuel pressure, and an electriccircuit for energizing said solenoid.

3. A device of the type described, comprising a fuel tank, couplingmeans for said tank, nozzle means for introducing fuel into an engine, aconduit connecting said nozzle means with said coupiing means, valvemeans including an axially movable valve needle and inserted in saidconduit, a tubular non-magnetic housing, a solenoid mounted on saidhousing, a tubular iron core movable within said housing, said valveneedle being placed within said iron core, a member on said Valve'needle for guiding the latter in said housing, a spring inserted insaid housing between said iron core and said member to transmit movementfrom the core to the valve needle in the valve opening direction againstthe action of fuel pressure, another spring inserted in said housing andacting on the valve needle in the valve closing direction, and anelectric circuit for energizing said solenoid.

4. In a device of the type described, nozzle means for introducingstarting fuel into an engine, means for connecting said nozzle meanswith a source of fuel under pressure, a valve housing connected in thepath of the fuel to, and in the proximity of, said nozzle means, a valveseat at one end of said housing near said nozzle means, a light-weightvalve member of small sealing area in relation to its length providedwithin said housing and cooperating with said seat to keep the valveclosed under the action of the fuel pressure, an impact member providedwithin said housing, an elastic intermediate member between said valvemember and said impact member, and` means for causing said impact memberby compressing said intermediate member to build up a force on saidvalve member suicient to move the latter away from its seat against thefuel pressure. Y

5. Ina device of the type described, nozzle means for introducingstarting fuel into an engine, means for connecting said nozzle meanswith a source of fuel under pressure, a tubular valve housing connectedin the path of the fuel to, and in theV proximityof, said nozzle means,a valve seat at one end of said housing near said nozzle means, alight-weight valve needle member provided within said housing andcooperating with said seat to keep the valve closed under the action ofthe fuel pressure, an impact member provided within said tubular housingand movable axially therein, an elastic intermediate member between saidvalve needle member and said impact member, and means for causing saidimpact member by compressing said intermediate member to build up aforce on said valve member sufficient to move the latter away from itsseat against the fuel pressure.

6. In a device of the type described, nozzle means for introducingstarting fuel into an engine, means for connecting said nozzle meanswith a source of fuel under pressure, a tubular valve housing connectedin the path of the fuel to, and in the proximity of, said nozzle means,a valve seat at one end of said housing near said nozzle means, alight-weight valve needle member provided within said housing andcooperating with said seat to keep the valve closed under the action ofthe fuel pressure, a tubular impact member provided within said housingand surrounding said Valve needle member, an elastic intermediate memberbetween said valve needle member and said impact member, and means forcausing said impact member by compressing said intermediate member tobuild up a force on said valve needle member suflicient to move thelatter away from its seat against the fuel pressure.

7. In a device of the type described, nozzle means for introducingstarting fuel into an engine,'means for connecting said nozzle meanswith a source of fuel under pressure, a tubular non-magnetic valvehousing connected in the path of the fuel to, and in the proximity of,said nozzle means, a valve seat at one end of said housing near saidnozzle means, a light-weight valve needle member provided within saidhousing and cooperating with said seat to keep the valve closed underthe action of the fuel pressure, a tubular iron core movable axiallywithin said housing and surrounding said valve needle member separatefrom the latter, an elastic intermediate member between said valveneedle member and said iron core, and a solenoid for causing said ironcore by compressing said intermediate member Ito build up a force onsaid valve needle member sufficient to move the latter away from itsseat against the fuel pressure.

8. In a device of the type described, nozzle means for introducingstarting fuel into an engine, means for connecting said nozzle meanswith a source of fuel under pressure, a tubular valve housing connectedin the path of the fuel to, and in the proximity of, said nozzle means,a valve seat at one end of said housing near said nozzle means, alight-weight valve needle member provided within said housing andcooperating with said seat to keep the valve closed under the action ofthe fuel pressure, a disc member mounted on said valve needle member atthe end there.. of remote from the valve seat for guiding the valveneedle member in said housing, a tubular iron core movable axiallywithin said housing and surrounding said valve needle member, an elasticintermediate member inserted in said housing between said disc memberand said iron core, and a solenoid for causing said iron core bycompressing said intermediate member to build up a force on said valveneedle member sufficient to move the latter away from its seat againstthe fuel pressure.

9. In a device of the type described, nozzle means for introducingstarting fuel into an engine, means for connecting said nozzle meanswith a source of fuel under pressure, a tubular valve housing connectedin the path of the fuel to, and in the proximity of, said nozzle means,a valve seat at one end of said housing near said nozzle means, alight-weight valve needle member provided within said housing andcooperating with said seat to keep the valve closed un-der the action ofthe fuel pressure, a disc member mounted on said valve needle member atthe end thereof remote from the valve seat for guiding the valve needlemember in said housing, said disc having a radial play in said housinglarger Ithan the maximum size of any solid particles that may becontained in the fuel and corresponding to negligible vibratory anglesof deviation of said valve needle member, a tubular iron core movableaxially within said housing and surrounding said valve needle member, anelastic intermediate member inserted in said housing between said discmember and said iron core ,and a solenoid for causing said iron core bycompressing said intermediate member to build up a force on said valveneedle member suflicient lto move the latter away from its seat againstthe fuel pressure.

10. In a device of the type described, nozzle means for introducingstarting fuel into an engine, means for connecting said nozzle meanswith a source of fuel under pressure, a tubular valve housing connectedin the path of the fuel to, and in the proximity of, said nozzle means,a valve seat at one end of said housing near said nozzle means, alight-weight valve needle member provided within said housing andcooperating with said seat to keep the valve closed under the action ofthe fuel pressure, a disc member mounted on said valve needle member atthe end thereof remote from the valve seat for guiding the valve needlemember in said housing, a tubular iron core movably axially within saidhousing and surrounding said valve needle member, a spiral Springinserted in said housing around said valve needle member between saiddisc member and said iron core, and a solenoid for causing said ironcore by compressing said spring to build up a force on said valve needlemember suicient to move the latter away from its seat against the fuelpressure.

11. In a device of the type described, a fitting to be mounted in anopening in the manifold of an engine, nozzle means for introducingstarting fuel into the engine mounted on the inner side of said tting,valve means provided on the outer side of said fitting and communicatingwith said nozzle means through a channel in said fitting, and means forconnecting said valve means with a source of fuel under pressure, saidvalve means comprising a Valve housing, a valve seat at the inner endthereof, a light-weight valve member of small sealing area in relationto its length provided within said housing and cooperating with saidseat to keep the valve closed under the action of the fuel pressure, andmeans for moving said valve member away from its seat against Athe fuelpressure.

Bo N. HoFFs'rRM.

